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Commit ea4054a23 (modpost: handle huge numbers of modules) added
support for building a large number of modules.
Unfortunately, the commit changed the semantics of the makefile: Instead of
passing only existing object files to modpost, make now passes all expected
object files. If make was started with option -i, this results in a modpost
error if a single file failed to build.
Example with the current btrfs build falure on m68k:
fs/btrfs/btrfs.o: No such file or directory
make[1]: [__modpost] Error 1 (ignored)
This error is followed by lots of errors such as:
m68k-linux-gcc: error: arch/m68k/emu/nfcon.mod.c: No such file or directory
m68k-linux-gcc: fatal error: no input files
compilation terminated.
make[1]: [arch/m68k/emu/nfcon.mod.o] Error 1 (ignored)
This doesn't matter much for normal builds, but it is annoying for builds
started with "make -i" due to the large number of secondary errors.
Those errors unnececessarily clog any error log and make it difficult
to find the real errors in the build.
Fix the problem by adding a new parameter '-n' to modpost. If this parameter
is specified, modpost reports but ignores missing object files.
With this patch, error output from above problem is (with make -i):
m68k-linux-ld: cannot find fs/btrfs/ioctl.o: No such file or directory
make[2]: [fs/btrfs/btrfs.o] Error 1 (ignored)
...
fs/btrfs/btrfs.o: No such file or directory (ignored)
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael Marek <mmarek@suse.cz>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
153 lines
5.2 KiB
Makefile
153 lines
5.2 KiB
Makefile
# ===========================================================================
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# Module versions
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# ===========================================================================
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#
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# Stage one of module building created the following:
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# a) The individual .o files used for the module
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# b) A <module>.o file which is the .o files above linked together
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# c) A <module>.mod file in $(MODVERDIR)/, listing the name of the
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# the preliminary <module>.o file, plus all .o files
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# Stage 2 is handled by this file and does the following
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# 1) Find all modules from the files listed in $(MODVERDIR)/
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# 2) modpost is then used to
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# 3) create one <module>.mod.c file pr. module
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# 4) create one Module.symvers file with CRC for all exported symbols
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# 5) compile all <module>.mod.c files
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# 6) final link of the module to a <module.ko> file
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# Step 3 is used to place certain information in the module's ELF
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# section, including information such as:
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# Version magic (see include/linux/vermagic.h for full details)
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# - Kernel release
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# - SMP is CONFIG_SMP
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# - PREEMPT is CONFIG_PREEMPT
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# - GCC Version
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# Module info
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# - Module version (MODULE_VERSION)
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# - Module alias'es (MODULE_ALIAS)
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# - Module license (MODULE_LICENSE)
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# - See include/linux/module.h for more details
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# Step 4 is solely used to allow module versioning in external modules,
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# where the CRC of each module is retrieved from the Module.symvers file.
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# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
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# symbols in the final module linking stage
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# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
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# This is solely useful to speed up test compiles
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PHONY := _modpost
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_modpost: __modpost
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include include/config/auto.conf
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include scripts/Kbuild.include
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# When building external modules load the Kbuild file to retrieve EXTRA_SYMBOLS info
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ifneq ($(KBUILD_EXTMOD),)
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# set src + obj - they may be used when building the .mod.c file
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obj := $(KBUILD_EXTMOD)
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src := $(obj)
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# Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
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include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
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$(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
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endif
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include scripts/Makefile.lib
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kernelsymfile := $(objtree)/Module.symvers
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modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
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# Step 1), find all modules listed in $(MODVERDIR)/
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MODLISTCMD := find $(MODVERDIR) -name '*.mod' | xargs -r grep -h '\.ko$$' | sort -u
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__modules := $(shell $(MODLISTCMD))
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modules := $(patsubst %.o,%.ko, $(wildcard $(__modules:.ko=.o)))
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# Stop after building .o files if NOFINAL is set. Makes compile tests quicker
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_modpost: $(if $(KBUILD_MODPOST_NOFINAL), $(modules:.ko:.o),$(modules))
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# Step 2), invoke modpost
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# Includes step 3,4
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modpost = scripts/mod/modpost \
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$(if $(CONFIG_MODVERSIONS),-m) \
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$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a,) \
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$(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
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$(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
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$(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(KBUILD_EXTRA_SYMBOLS))) \
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$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
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$(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S) \
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$(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
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MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS)))
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# We can go over command line length here, so be careful.
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quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
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cmd_modpost = $(MODLISTCMD) | sed 's/\.ko$$/.o/' | $(modpost) $(MODPOST_OPT) -s -T -
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PHONY += __modpost
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__modpost: $(modules:.ko=.o) FORCE
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$(call cmd,modpost) $(wildcard vmlinux)
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quiet_cmd_kernel-mod = MODPOST $@
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cmd_kernel-mod = $(modpost) $@
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vmlinux.o: FORCE
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$(call cmd,kernel-mod)
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# Declare generated files as targets for modpost
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$(symverfile): __modpost ;
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$(modules:.ko=.mod.c): __modpost ;
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# Step 5), compile all *.mod.c files
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# modname is set to make c_flags define KBUILD_MODNAME
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modname = $(notdir $(@:.mod.o=))
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quiet_cmd_cc_o_c = CC $@
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cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \
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-c -o $@ $<
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$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
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$(call if_changed_dep,cc_o_c)
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targets += $(modules:.ko=.mod.o)
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# Step 6), final link of the modules
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quiet_cmd_ld_ko_o = LD [M] $@
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cmd_ld_ko_o = $(LD) -r $(LDFLAGS) \
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$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
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-o $@ $(filter-out FORCE,$^)
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$(modules): %.ko :%.o %.mod.o FORCE
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$(call if_changed,ld_ko_o)
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targets += $(modules)
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# Add FORCE to the prequisites of a target to force it to be always rebuilt.
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# ---------------------------------------------------------------------------
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PHONY += FORCE
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FORCE:
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# Read all saved command lines and dependencies for the $(targets) we
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# may be building above, using $(if_changed{,_dep}). As an
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# optimization, we don't need to read them if the target does not
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# exist, we will rebuild anyway in that case.
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targets := $(wildcard $(sort $(targets)))
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cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
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ifneq ($(cmd_files),)
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include $(cmd_files)
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endif
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# Declare the contents of the .PHONY variable as phony. We keep that
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# information in a variable se we can use it in if_changed and friends.
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.PHONY: $(PHONY)
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